Effectiveness of the Gregory-Loredo Algorithm for the Detection of Temporal Variability in Chandra Data

摘要

In searching for a reliable variability indicator for Chandra X-ray event data, we implemented and tested the Gregory-Loredo (Gre-gory & Loredo 1992) algorithm. The test was performed on 118 sourcesdetected in a single observation, spanning the intensity range of 5 to 24000 photons over a total observing time of 102000 s. The G-L algorithm isextremely robust, yielding a reliable variability indicator as well as a lightcurve with optimal resolution while requiring a very modest amount ofCPU time. The algorithm can also work on binned data and handle datagaps as well as variations in effective area.